Bonjour,
-2x^2 - x - 3 = 0
Delta = (-1)^2 - 4 * (-2) * (-3)
Delta = 1 - 24 < 0 pas de solution
x^2 - 10x + 25 = 0
Delta = (-10)^2 - 4 * 1 * 25
Delta = 100 - 100 = 0 une solution unique
X1 = X2 = (10)/(2 * 1) = 5
-x^2 - 9x + 10 = 0
Delta = (-9)^2 - 4 * (-1) * 10
Delta = 81 + 40
Delta = 121
Vdelta = V121 = 11 > 0 deux solutions possibles
X1 = (-9 - 11)/(2 * -1) = -20/-2 = 10
X2 = (-9 + 11)/(2 * -1) = 2/-2 = -1
-3x^2 + 6x - 2 = 0
Delta = 6^2 - 4 * -3 * -2
Delta = 36 - 24 = 12
Vdelta = V12 = 2V3 > 0 2 solutions
X1 = (6 - 2V3)/(2 * -3) = (6 - 2V3)/(-6) = -1 + V3/3
X2 = (6 + 2V3)/(2 * -3) = (6 + 2V3)/(-6) = -1 - V3/3